Method and apparatus for producing fiber-reinforced resin molding material

ABSTRACT

Provided are a method and an apparatus for manufacturing a fiber-reinforced resin molding material by which, when the fiber-reinforced resin molding material is manufactured, separated fiber bundles can be supplied to a cutting machine in stable condition while avoiding the influence of meandering of the fiber bundles or slanting or meandering of filaments occurring in the fiber bundles.

TECHNICAL FIELD

The present invention relates to a method and an apparatus for producinga fiber-reinforced resin molding material.

The present application is based upon, and claims the benefit of,priority to Japanese Application Nos. 2015-136084, filed Jul. 7, 2015,and 2016-078937, filed Apr. 11, 2016, the entire contents of which areincorporated herein by reference.

BACKGROUND ART

As for molding materials that exhibit excellent mechanicalcharacteristics in molded articles and are suitable for molding complexfeatures such as three-dimensional shapes, sheet molding compounds(SMCs) and stampable sheets are known, SMCs are sheet-typefiber-reinforced resin molding materials formed by impregnatingthermosetting resins such as unsaturated polyester resins amongfilaments of cut fiber bundles of reinforcing fibers, for example, glassfibers and carbon fibers. Stampable sheets are sheet-typefiber-reinforced resin molding materials formed by impregnatingthermoplastic resins into the above-mentioned cut fiber bundles, forexamples.

An SMC is an intermediate material for obtaining molded articles. In amolding process, an SMC is compression-molded (pressed) in a die whileheat is applied on the SMC. During that time, fiber bundles and athermosetting resin are integrated and flowed to fill the cavity of adie, and the thermosetting resin is cured therein. Thus, SMCs arecapable of forming molded articles with various shapes, for example,articles having partially different thicknesses or having ribs andbosses. Molded articles made of a stampable sheet are obtained byheating the stampable sheet at or above the melting point of thethermoplastic resin using an infrared heater or the like, and then bycompressing the sheet while cooling it in a die set at a predeterminedtemperature.

In the above-mentioned production process of, an SMC (fiber-reinforcedresin molding material), after a paste containing a thermosetting resinis coated on a sheet (carrier) while the sheet is transported,continuous fiber bundles, cut with a cutter to a predetermined length,are spread on the paste (see Patent Literatures 1 and 2, for example).

In addition, to lower the production cost of SMCs, a relatively low-costfiber bundle, called a large tow, having a greater number of filamentsis used; the fiber bundle is first widened in a width direction(referred to as fiber opening), the opened fiber bundle is divided intomultiple fiber bundles (referred to as fiber separation), and then theseparated fiber bundles are cut with a cutter.

However, in conventional production methods, when filaments become askewor meander in fiber bundles, some of the opened fiber bundles remainunseparated, or some fiber bundles break, possibly causing, an unstable′supply of opened and separated fiber bundles to a cutter. The samesituation may be observed with stampable sheets.

More specifically, Patent Literature 1 discloses a method for separatingopened fiber bundles by piercing the bundles with protruding objects.However, when such a method is used, if filaments in fiber bundles areaskew or meandering, fiber bundles that are supposed to be separatedwill remain unseparated, after the cutting process. Accordingly, thereis a risk of having unseparated fiber bundles.

Meanwhile, Patent Literature 2 discloses a method for continuouslyseparating opened fiber bundles by using a rotary blade in rotationalmotion. However, when such a method is used, if filaments become askewor meander in fiber bundles, some of the separated fiber bundles break,and broken fiber bundles may wrap around the roll or the like.

CITATION LIST Patent Literature

Patent Literature 1: Specification of US2012/0213997 A1

Patent Literature 2: JP2006-219780A

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

The present invention was carried out in consideration of conventionalproblems described above. Its objective is to provide a method andapparatus for producing a fiber-reinforced resin molding materialcapable of supplying separated fiber bundles in a stable condition tothe cutter when producing a sheet-type fiber-reinforced resin moldingmaterial formed by impregnating a resin among filaments of cut fiberbundles, while maintaining the quality of fiber-reinforced resin moldingmaterial and avoiding impact stemming from meandering fiber bundles oraskew or meandering filaments that may occur in fiber bundles.

Solutions to the Problems

To achieve the above objective, the present invention, provides thefollowing.

[1] A method for producing a sheet-type fiber-reinforced resin moldingmaterial that is formed by impregnating a resin among filaments of cutfiber bundles,

in which the cut fiber bundles are obtained by intermittently separatinga continuous fiber bundle in a longitudinal direction and by cutting thefiber bundles at intervals in the longitudinal direction to satisfy thecondition specified in formula (1) below.

1≤a/L  (1)

(In formula (1). “a” is the length, of a separated portion of thecontinuous fiber bundle, and “L” is the interval for cutting the fiberbundles in a longitudinal direction.)[2] The method for producing a fiber-reinforced resin molding materialaccording to [1], in which separation and cutting are conducted tofurther satisfy the condition specified in formula (2) below.

a/L≤10  (2)

[3] A method for producing a sheet-type fiber-reinforced resin moldingmaterial that is formed by impregnating a resin among filaments of cutfiber bundles,

in which the cut fiber bundles are obtained by intermittently separatinga continuous fiber bundle in a longitudinal direction and by cutting thefiber bundles at intervals in the longitudinal direction to satisfy thecondition specified in formula (3) below,

0.9≤a/(a+b)<1  (3)

(In formula (3), “a” is the length of a separated portion of thecontinuous fiber bundle, and “b” is the length of an unseparated portionthat is present between portions intermittently separated in thecontinuous fiber bundle.)[4] The method for producing a fiber-reinforced resin molding materialaccording to any of [1]˜[3], in which the resin is a thermosettingresin.[5] The method for producing a fiber-reinforced resin molding materialaccording to any of [1]˜[4], in which the intermittent separation isconducted by intermittently piercing the continuous fiber bundle with ablade.[6] The method for, producing a fiber-reinforced resin molding materialaccording to any of [1]˜[5], in which a series of multiple blades,aligned at predetermined intervals in a width direction of thecontinuous fiber bundle, pierce the continuous fiber bundleintermittently so as to form partially unseparated portions amongmultiple separated fiber bundles.[7] The method for producing a fiber-reinforced resin molding materialaccording to any of [1]˜[6], including: a step for coating aresin-containing paste on a first sheet transported in a predetermineddirection; a step for separating a continuous fiber bundle into multiplefiber bundles; a step for cutting the separated fiber bundles with acutter and spreading the cut fiber bundles on the paste; and a step forimpregnating the resin among filaments of the fiber bundles bylaminating, a second sheet with the coated paste onto the first sheetwith the fiber bundles spread thereon and by compressing, the paste andfiber bundles sandwiched between the first and second sheets.[8] The method for producing a fiber-reinforced resin molding materialaccording to [7], in which in the step for separating a continuous fiberbundle into multiple fiber bundles, multiple rotary blades, aligned atpredetermined intervals in a width direction of a continuous fiberbundle and each having a series of multiple teeth in its circumferentialdirection, are used so that the multiple teeth intermittently pierce thecontinuous fiber bundle while the multiple rotary blades rotate.[9] The method for producing a fiber-reinforced resin molding materialaccording to [7], in which in the step for separating a continuous fiberbundle into multiple fiber bundles, saw blades with multiple teeth,aligned in a direction the same as the transport direction of the fiberbundle, are used so that the multiple teeth intermittently pierce thecontinuous fiber bundle while the saw blades oscillate vertically.[10] The method for producing a fiber-reinforced resin molding materialaccording to any of [7]˜[9], in which in the step for, separating acontinuous fiber bundle into multiple fiber bundles, continuous fiberbundles are laminated in a thickness direction and are separated intomultiple fiber bundles.[11] The method for producing a fiber-reinforced resin molding materialaccording to any of [7]˜[10], in which in the step for separating acontinuous fiber bundle into multiple fiber bundles, the continuousfiber bundle is opened in the width direction, and then the opened fiberbundle is separated into multiple fiber bundles.[12] An apparatus for producing a sheet-type fiber-reinforced resinmolding material that is formed by impregnating a resin among filamentsof cut fiber bundles, including a separation unit for separating acontinuous fiber bundle into multiple fiber bundles, and a cutting unitfor cutting separated fiber bundles with a cutter, in which theseparation unit forms partially unseparated portions among multipleseparated fiber bundles by intermittently piercing the continuous fiberbundle with a blade.[13] The apparatus for producing a fiber-reinforced resin moldingmaterial according to [12], in which the blade is set to be a series ofmultiple blades aligned at predetermined intervals in a width directionof the continuous fiber bundle.[14] The apparatus for producing a fiber-reinforced resin moldingmaterial according to [12] or [13], including: a coating unit forcoating a resin-containing paste on a first sheet transported in apredetermined direction; the separation unit; a cutting unit for cuttingthe separated fiber bundles with a cutter and spreading the cut fiberbundles on the paste; and an impregnation unit for impregnating theresin among filaments of the fiber bundles by laminating a second sheetwith the coated paste onto the first sheet with the fiber bundles spreadthereon and by compressing the paste and fiber bundles sandwichedbetween the first and second sheets.[15] The apparatus for producing a fiber-reinforced resin moldingmaterial according to any of [12]˜[14], in which the separation unitincludes rotary blades with multiple teeth aligned in itscircumferential direction and the multiple teeth pierce the continuousfiber bundle intermittently when the rotary blades rotate.[16] The apparatus for producing a fiber-reinforced resin moldingmaterial according to any of [12]˜[14], in which the separation unitincludes saw blades with multiple teeth aligned in a direction the sameas the transport direction of the fiber bundle and the multiple teethintermittently pierce a continuous fiber bundle while the saw bladesoscillate vertically.[17] The apparatus for producing a fiber-reinforced resin, moldingmaterial according to any of [12]˜[16], further comprising paired guidemembers positioned on both sides of the blade in the transportdirection, and from the side opposite where the paired guide members arepositioned, the blade pierces the continuous fiber bundle transportedbetween the paired guide members.[18] The apparatus for producing a fiber-reinforced resin moldingmaterial according to any of [13]˜[17], further comprising a spacermember positioned between multiple blades aligned in a width direction,in which the multiple blades pierce the continuous fiber bundle up tothe point where the spacer member makes contact with the bundle.

Effects of the Invention

As described, by forming partially unseparated portions among multiple,separated fiber bundles, separated fiber bundles are supplied to thecutter in a stable condition and the quality of fiber-reinforced resinmolding material is maintained while avoiding the impact stemming fromaskew or meandering filaments that may occur in fiber bundles.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view showing the structure of an SMC productionapparatus according to an embodiment of the present invention;

FIG. 2A is a side view showing a structural example of a fiber bundlesupply unit equipped in the SMC production apparatus shown in FIG. 1;

FIG. 2B is a front view of a separation unit seen from the transportdirection, showing a structural example of a fiber bundle supply unitequipped in the SMC production apparatus shown in FIG. 1;

FIG. 3 is a schematic view showing the separation positions of separatedfiber bundles;

FIG. 4A is a side view showing another structural example of a fiberbundle supply unit equipped in the SMC production apparatus shown inFIG. 1;

FIG. 4B is a front view of a separation unit seen from the transportdirection, showing another structural example of a fiber bundle supplyunit equipped in the SMC production apparatus shown in FIG. 1;

FIG. 5A is a side view showing an, example of the shape of a blade;

FIG. 5B is a side view showing another example of the shape of a blade;

FIG. 5C is a side view showing yet another example of the shape of ablade;

FIG. 5D is a side view showing yet another example of the shape of ablade;

FIG. 5E is a side view showing yet another example of the shape of ablade;

FIG. 6A is a schematic view illustrating the point angle of a blade; and

FIG. 6B is a schematic view illustrating the cutting edge angle of ablade.

DETAILED DESCRIPTION OF THE EMBODIMENTS

in the following, embodiments of the present invention are described indetail referring to the attached drawings.

The material, dimensions and the like listed in the descriptions beloware examples. The present invention is not limited to those examples,and may also be practiced through appropriate modifications within ascope that does not deviate from the gist of the present invention.

[Method for Producing Fiber-Reinforced Resin Molding Material]

The production method related to the present invention is for producinga sheet-type fiber-reinforced resin molding material formed byimpregnating a resin among filaments of cut fiber bundles. The method isapplicable for producing SMCs, stampable sheets and the like.

A fiber bundle is formed by bundling multiple reinforcing fibers. As forreinforcing fibers, carbon fibers are preferred, but that is not theonly option. Reinforcing fibers are not limited to carbon fibers. Otherreinforcing fibers such as glass fibers may also be used.

Examples of a resin are thermosetting resins and thermoplastic resins;it is an option to use only a thermosetting resin or a thermoplasticresin, or use both thermosetting and thermoplastic resins. Whenfiber-reinforced resin material of the present embodiment is used as anSMC, using a thermosetting resin is preferred. When fiber-reinforcedresin material of the present embodiment is used as a stampable sheet,using a thermoplastic resin is preferred.

Examples of a thermosetting resin are unsaturated polyester resins,epoxy resins, vinyl ester resins, phenol resins, epoxy acrylate resins,urethane acrylate resins, phenoxy resins, alkyd resins, urethane resins,maleimide resins, cyanate resins and the like. Those thermosettingresins may be used alone or in combination thereof.

Examples of a thermoplastic resin are polyolefin resins, polyamideresins, polyester resins, polyphenylene sulfide resins, polyether ketoneresins, polyether sulfone resins,

aromatic polyamides resins and the like. Those thermoplastic resins maybe used alone or in combination thereof.

In an embodiment of the method for producing a fiber-reinforced resinmolding material according to the present invention, the cut fiberbundles are obtained by intermittently separating a continuous fiberbundle in a longitudinal direction and by cutting the fiber bundle atintervals in the longitudinal direction so as to satisfy the conditionspecified in formula (1) below.

1≤a/L  (1)

Note that in formula (1). “a” is the length of a separated portion of acontinuous fiber bundle, and “L” is the interval for cutting the fiberbundle in a longitudinal direction.

When the Value of “a/L” is smaller than 1, namely, when the length “a”of a separated portion is less than the interval “L” of a fiber bundleto be cut in a longitudinal direction, there is at least one unseparatedportion in each cut portion of the fiber bundle. Therefore, it isdifficult to homogeneously disperse reinforcing fibers in a productionprocess of an SMC, for example, and the result of impregnating resin islowered. Accordingly, the quality of the produced SMC tends to besignificantly decreased. The value of “a/L” is preferred to be at least1.05, more preferably at least 1.1.

Moreover, separation and cutting of fiber bundles in the presentinvention are preferred to be conducted to satisfy the conditionspecified in formula (2) below.

a/L≤10  (2)

When the value of “a/L” is no greater than 10, even when filaments in afiber bundle to be separated are askew or meandering, occurrence offluff in cut fiber bundles along, with process failure caused by fluffis more likely to be suppressed. The value of “a/L” is preferred to beno greater than 8, more preferably no greater than 5.

In another embodiment of the method for producing a fiber-reinforcedresin molding material according to the present invention, a continuousfiber bundle is intermittently separated in a longitudinal direction andis cut at longitudinal intervals so as to obtain cut fiber bundles thatsatisfy the condition specified in formula (3) below.

0.9≤a/(a+b)<1  (3)

In formula (3), “a” is the length of a separated portion of a continuousfiber bundle, and “b” is the length of an unseparated portion that ispresent between portions intermittently separated in the continuousfiber bundle.

When the value of “a/(a+b)” is smaller than 0.9, unseparated portions ofcut fiber bundles are likely to be undetached when fiber bundles arespread on a paste in a production process of an SMC, for example. Thus,it is difficult to homogeneously disperse reinforcing fibers on thepaste, and the results of impregnating resin into reinforcing fibers arelowered. Accordingly, the quality of the produced SMC tends to bedecreased. The value of “a/(a+b)” is preferred to be at least 0.92.

When there is no unseparated portion (b=0), a fiber bundle iscontinuously separated, and the value of “a/(a+b)” is 1. However, insuch a case where there is no unseparated portion, if the fiber bundlemeanders or filaments in the fiber bundle are askew or meandering, someof the separated fiber bundles break, and the cut fiber bundles may raparound a roll or the like. In the present invention, since a continuousfiber bundle is intermittently separated in its longitudinal direction,“b” is greater than zero (b>0), namely, a/(a+b)<1.

To supply separated fiber bundles to a cutter in a stable condition, thevalue of “a/(a+b)” is preferred to be no greater than 0.99, morepreferably no greater than 0.98.

In the method for producing a fiber-reinforced resin molding materialrelated to the present invention it is preferred to separate and cutfiber bundles to simultaneously satisfy conditions specified in formulas(1) and (3). By so setting, when a fiber bundle is cut, at least someportions are separated. Accordingly, it is easier to prevent unseparatedfiber bundles from remaining among cut fiber bundles. Even if someunseparated portions remain, they will be dispersed during the processof spreading fibers since the majority of cut fiber bundles areseparated. Accordingly, the quality of the produced SMC is unlikely tobe affected.

To intermittently separate a continuous fiber bundle, it is preferredfor a blade to intermittently pierce a continuous fiber bundle in itslongitudinal direction since a more stable separation process isconducted. Furthermore, it is more preferred to intermittently pierce acontinuous fiber bundle by using a series of multiple blades aligned atpredetermined intervals in a width direction of the continuous fiberbundle so that partially unseparated portions are made among theseparated multiple fiber bundles.

In the present invention, a blade means an object in a plate shape, itstip that touches a fiber bundle first is set narrow and thin, and thecross section of the tip is substantially in a wedge shape. Examples ofthe material of a blade are hard materials such as metals or ceramics.

The shape of a blade is not limited specifically as long as it iscapable of piercing a fiber bundle. Considering the durability of ablade and its capability of separating fibers, the maximum thickness ofa blade that touches a fiber bundle is preferred to be 0.3˜2 mm. Themaximum width of a blade that touches a fiber bundle is preferred to be0.5˜1.5 mm. The angle of the tip portion of a blade in its widthdirection (point angle) is preferred to be 30°˜90°. The angle of a bladein a thickness direction (cutting edge angle) is preferred to be10°˜45°, more preferably 20°˜30°.

The point angle means the angle of the tip of a blade when the planarportion of the blade is seen from the front. The cutting edge anglemeans the angle at the tip of a blade when a side surface of the blade(the plane in a thickness direction) is seen from the front.

As a method for intermittently separating a continuous fiber bundle,instead of using a blade, a gas such as air, for example, may be sprayedunder predetermined conditions on the above fiber bundle.

An example of a method for producing a fiber-reinforced resin moldingmaterial is the method below, including a coating step, separation step,cutting step and impregnation step:

a coating step: coat a resin-containing paste on a first sheet beingtransported in a predetermined direction;

a separation step: separate a continuous fiber bundle into multiplefiber bundles;

a cutting step: cut the separated fiber bundles with a cutter and spreadthem on the paste; and

an impregnation step: impregnate the resin among filaments of the fiberbundles by laminating a second sheet with the coated paste onto thefirst sheet with fiber bundles spread thereon, and by compressing thepaste and fiber bundles sandwiched between the first and second sheets.

In the separation step and cutting step, fiber bundles are separated andcut to satisfy either or both of conditions (1) and (3) above so thatseparated fiber bundles are supplied to the cutter in a stable conditionwhile avoiding being impacted by askew or meandering filaments that mayoccur in the fiber bundles.

In the separation step, it is preferred to use multiple rotary blades,each having a series of multiple teeth in its circumferential direction,aligned at predetermined intervals in a width direction of a continuousfiber bundle, so that the multiple teeth intermittently pierce thecontinuous fiber bundle while the rotary blades rotate. Alternatively,it is also preferred to use saw blades with multiple teeth aligned in adirection the same as the transport direction of the fiber bundle sothat the multiple teeth intermittently pierce the continuous fiberbundle while the saw blades oscillate vertically.

In the separation step, it is preferred to separate continuous fiberbundles into multiple fiber bundles when laminated in a thicknessdirection.

In addition, after a continuous fiber bundle is opened in a widthdirection, it is preferred to separate the opened fiber bundle intomultiple fiber bundles in the separation step. In other words, it ispreferred to further include an opening step for opening a continuousfiber bundle in a width direction prior to a separation step.

[Apparatus for Producing Fiber-Reinforced Resin Molding Material]

An apparatus for producing a fiber-reinforced resin molding materialaccording to an embodiment of the present invention is described belowin detail by referring to an SMC production apparatus shown in FIGS. 1and 2, for example. The SMC production apparatus in the presentembodiment is intended to produce a sheet-type SMC (Sheet MoldingCompound), which contains fiber bundles made of carbon fibers and athermosetting resin made of an unsaturated polyester resin, and isformed by impregnating the thermosetting resin among filaments of cutfiber bundles. Here, it is an option to use other reinforcing fiberssuch as glass fibers as the fiber bundles instead of carbon fibers andto use a thermoplastic resin instead of a thermosetting resin.

FIG. 1 is a side view showing the structure of an SMC production,apparatus. FIG. 2A is a side view showing a structural example of fiberbundle supply unit 10 in the SMC production apparatus shown in FIG. 1.FIG. 2B is a front view of the separation unit seen from the transportdirection. Moreover, in descriptions below, an XYZ rectangularcoordinate system is set and positional relationships among members aredescribed in accordance with the XYZ rectangular coordinate system.

As shown in FIG. 1, the SMC production apparatus of the present,embodiment includes fiber bundle supply unit 10, first sheet supply unit11, first coating unit 12, cutting unit 13, second sheet supply unit 14,second coating unit 15 and impregnation unit 16.

As enlarged in FIG. 2A, fiber bundle supply unit 10 is structured tohave an opening unit for opening a continuous fiber bundle CF in a widthdirection (axis (Y) direction) while transporting the fiber bundle in apredetermined direction (hereinafter referred to as a transportdirection), and a separation Unit for separating the opened fiber bundleCF into multiple fiber bundles CF.

More specifically, fiber bundle supply unit 10 includes multiple openingbars 17, multiple rotary blades 18 and multiple godet rollers 19.

In fiber bundle supply unit 10, first, a large-tow fiber bundle CF isopened in its width direction by being drawn from bobbin B in an axis(+X) direction in FIG. 1 (in the horizontally right direction). Morespecifically, while passing through multiple opening bars 17 of theopening unit, a fiber bundle CF is widened in its width direction byusing, for example, heat, abrasion, oscillation or the like at eachopening bar 17.

The opened fiber bundle CF is separated into multiple fiber bundles CFby multiple rotary blades 18 in the separation unit. Multiple rotaryblades 18 are aligned at predetermined intervals in a width direction ofthe opened fiber bundle CF (axis (Y) direction). A series of multipleteeth 18 a are set in a circumferential direction of each rotary blade18. Among rotary blades 18, positions of multiple teeth 18 a arepreferred to correspond to each other in a circumferential direction. Byso setting, piercing is done more easily by each of teeth 18 a ofmultiple rotary blades 18 aligned in a width direction of fiber bundleCF.

As shown in FIG. 2B, spacer members 181) are disposed among rotaryblades 18. The circumferential surface of each spacer member 18 b ispositioned slightly above or slightly below the border of each of teeth18 a (blade base). By setting in such a positional relationship, thedepth of piercing is adjusted. Multiple rotary blades 18 are supportedto be rotatable. Accordingly, multiple rotary blades 18 are rotated in adirection the same as the transport direction of a fiber bundle CF whileteeth 18 a pierce the fiber bundle CF as it is transported. Multiplerotary blades 18 may be structured to be driven by a drive motor or thelike so as to synchronize the rotation with the transport of a fiberbundle CF.

A pair of guide members 40 are positioned respectively on both sides ofmultiple rotary blades 18 in the transport direction. Multiple rotaryblades 18 are positioned so that multiple teeth 18 a pierce a fiberbundle CF transported between paired guide members 40 from the sideopposite where paired guide members 40 are disposed.

A fiber bundle CF is separated in its width direction while rotaryblades 18 are rotated so that multiple teeth 18 a intermittently piercea continuous fiber bundle CF. During that time, multiple teeth 18 apierce to the point where spacer members 18 b make contact with acontinuous fiber bundle CF so as to prevent the fiber bundle CF fromcontinuously being separated by teeth 18 a. Accordingly, separatedmultiple fiber bundles CF are not completely separated from each other,and are partially unseparated. Then, separated fiber bundles CF aresupplied toward cutting unit 13 while being guided by multiple godetrollers 19.

First sheet supply unit 11 supplies continuous first sheet (S1) as it isunwound from first material roll (R) toward first coating unit 12. TheSMC production apparatus includes first transport unit 20 whichtransports first sheet (S1) toward impregnation unit 16.

First transport unit 20 includes conveyor 23 with endless belt 22spanned over a pair of pulleys (21 a, 21 b). Conveyor 23 rotates endlessbelt 22 circumferentially by rotating paired pulleys (21 a, 21 b) in thesame direction so, that first sheet (S1) placed on the surface ofendless belt 22 is transported in the axis (+X) direction in FIG. 1(horizontally toward the right).

First coating unit 12 includes coater 24 which is positioned directly onfirst sheet (S1) transported in the axis (+X) direction in FIG. 1(horizontally toward the right) and supplies paste (P). When first sheet(S1) passes under coater 24 in first coating unit 12, paste (P) iscoated at a predetermined thickness on the surface of first sheet (S1).

As paste (P), in addition to a thermosetting resin such as theabove-mentioned unsaturated polyester resins, a mixture may also be usedby adding a filler such as calcium carbonate, a shrinkage-reducingagent, release agent, curing initiator, thickener or the like.

Cutting unit 13 is positioned on the downstream side of first coatingunit 12 in the transport direction and cuts fiber bundles CF suppliedfrom fiber bundle supply unit 10 by using cutter 13A and spreadscut-fiber bundles on past (P). Cutter 13A is positioned above firstsheet (S1) transported by conveyor 23 and includes guide roller 25,pinch roller 26 and cutter miler 27.

Guide roller 25 rotates and guides fiber bundle CF supplied from fiberbundle supply unit 10 in the downstream direction. Pinch roller 26sandwiches fiber bundle CF with guide roller 25 and rotates in thedirection opposite that of guide roller 25 so as to cooperate with guideroller 25 to bring in separated fiber bundles CF. Cutter roller 27rotates and cuts fiber bundles CF to a predetermined length. Cut fiberbundles CF fall from between guide roller 25 and cutter roller 27 andare spread on first sheet (S1) (paste (P)).

Second sheet supply unit 14 supplies continuous second sheet (S2) as itis unwound from second material roll (R2) toward second coating unit 15.The SMC production apparatus includes second transport unit 28 whichtransports second sheet (S2) toward impregnation unit 16.

Second transport unit 28 is positioned above first sheet (S1)transported by conveyor 23 and includes, multiple guide rollers 29.Second transport unit 28 transports second sheet (S2) supplied fromsecond supply unit 14 in the axis (−X) direction in FIG. 1 (horizontallytoward the left), and then inverts the direction for transporting secondsheet (S2) from below by rotating multiple guide rollers 29 in the axis(+X) direction in FIG. 1 (horizontally toward the right).

Second coating unit 15 is positioned directly above second sheet (S2)transported in the axis (−X) direction in FIG. 1 (horizontally towardthe left) and includes coater 30 for supplying paste (P). In secondcoating unit 15, second sheet (S2) passes through coater 30 so thatpaste (P) is coated on the surface of second sheet (S2) at apredetermined thickness.

Impregnation unit 16 is positioned on the downstream side of cuttingunit 13 in the transport direction and includes lamination mechanism 31and compression mechanism 32. Lamination mechanism 31 is positionedabove downstream-side pulley 21 b of conveyor 23 and includes multiplelamination rollers 33.

Multiple lamination rollers 33 are positioned so as to make contact withthe hack surface of second sheet (S2) on which paste (P) is coated.Moreover, multiple lamination rollers 33 are positioned in such a waythat second sheet (S2) gradually approaches first sheet (S1).

By setting as above, second sheet (S2) is laminated on first sheet (S1).In addition, first sheet (S1) and second sheet (S2) sandwich fiberbundles CF and paste (P) between them and are transported towardcompression mechanism 32 in a laminated condition. In the following,first sheet (S1) and second sheet (S2) laminated together arecollectively referred to as laminate sheet (S3).

Compression mechanism 32 is positioned on the downstream side of firsttransport unit 20 (conveyor 23), and includes lower conveyor 36A withendless belt 35 a spanned between paired pulleys (34 a, 34 b) and, upperconveyor 36B with endless belt 35 b spanned between paired pulleys (34c, 34 d).

Lower conveyor 36A and upper conveyor 36B are positioned across fromeach other while endless belts (35 a, 35 b) are set to face each other.Compression mechanism 32 rotates paired pulleys (34 a, 34 b) of lowerconveyor 36A in the same direction to circle endless belt 35 a, whilerotating paired pulleys (34 c, 34 d) of upper conveyor 36B in the samedirection so that endless belt 35 b circles at the same speed as endlessbelt 35 a but in the opposite direction. By so setting, laminate sheet(S3) sandwiched between endless belts (35 a, 35 b) is transported in theaxis (+X) direction in FIG. 1 (horizontally toward the right).

Compression mechanism 32 includes multiple lower rollers 37 a andmultiple upper rollers 37 b. Multiple lower rollers 37 a are positionedto be in contact the back surface of the abutting portion of endlessbelt 35 a, in the same manner, multiple upper rollers 37 b arepositioned to be in contact with the back surface of the abuttingportion of endless belt 35 b. Multiple lower rollers 37 a and multipleupper rollers 37 b are alternately positioned in the transport directionof laminate sheet (S3).

Compression mechanism 32 compresses paste (P) and fiber bundles CFsandwiched between first sheet (S1) and second sheet (S2) using multiplelower rollers 37 a and multiple upper rollers 37 b while laminate sheet(S3) passes between endless belts (35 a, 35 b). During that time, paste(P) is impregnated into filaments of fiber bundles CF from both sidessandwiching fiber bundles CF. Accordingly, raw material (R) of SMC isobtained where a thermosetting resin is impregnated in filaments offiber bundles CF.

[Method for Producing SMC]

Regarding the method for producing a fiber-reinforced resin moldingmaterial according to an embodiment of the present invention, a methodfor producing an SMC is described below in detail by using theabove-mentioned SMC production apparatus.

In the method for producing an SMC of the present embodiment, long firstsheet (S1) is unwound from first material roll (R1) in a coating step,and paste (P) is coated on first sheet (S1) by first coating unit 12 ata predetermined thickness while first sheet (S1) is transported by firsttransport unit 20.

Then, in an opening step, a fiber bundle CF is passed through multipleopening bars 17 so that the fiber bundle CF is widened in a widthdirection.

Next, in a separation step, rotary blades 18 rotate so that multipleteeth 18 a intermittently pierce the opened fiber bundle CF.Accordingly, the fiber bundle CF is intermittently separated in alongitudinal direction so as to form partially unseparated portionsamong separated multiple fiber bundles CF. In the separation step, toprevent separated fiber bundles CF from attaching to each other, thetemperature of fiber bundle CF during separation is preferred to be 60°C. or lower, more preferably 50˜5° C.

Separation positions of separated fiber bundles CF are described byreferring to FIG. 3. In FIG. 3, a tow “t” of an opened fiber bundle CFis shown as a thin line, and a separation line of opened fiber bundle CFis shown as a bold line, and a cut line of opened fiber bundle CF to becut by cutter 134 is shown as a broken line.

In separated fiber bundles CF a portion separated by teeth 18 a and aportion not separated by teeth 18 a are formed alternately in aso-called perforated state as shown in FIG. 3.

In the above condition, even if filaments are askew, meandering orentangled in fiber bundle CF, filaments are partially connected to eachother among multiple separated fiber bundles CF. Accordingly, multipleseparated fiber bundles CF are transported in a stable condition towardcutter 13A as they maintain an open state in a width direction.Moreover, even when filaments are askew or meandering in a fiber bundleCF, no damage occurs in the fiber bundle CF. Therefore, separated fiberbundles CF are prevented from breaking, and process failure such as abroken fiber bundle CF wrapping around rolls or the like is therebypreventable.

As described above, in the method for producing an SMC of the presentembodiment, by forming partially unseparated portions among multipleseparated fiber bundles CF, separated fiber bundles CF are supplied tocutter 13A in a stable condition while avoiding being impacted bymeandering fiber bundles CF or askew, meandering or entangled filamentsthat may occur in fiber bundles CF. Moreover, using relatively low-costlarge-tow fiber bundles CF, the production cost of an SMC is reduced.

In a cutting step, fiber bundles CF separated in separation unit 13 arecut by cutter 13A, and spread on paste (P). In separation and cuttingsteps, fiber bundles are separated and cut to satisfy either or bothconditions of (1) and (3) described above. By so doing, it is easier tohomogeneously disperse reinforcing fibers and to enhance the result ofimpregnating resin. Accordingly, high quality SMCs are achieved.

In an impregnation step, long second sheet (S2) is unwound from secondraw material roll (R2) by second sheet supply unit 14, and paste (P) iscoated on second, sheet (S2) at a predetermined thickness by secondcoating unit 15. Next, in impregnation unit 16, lamination mechanism 31is used to laminate second sheet (S2) on first sheet (S1). Then, usingcompression mechanism 32, paste (F) and fiber bundles sandwiched betweenfirst sheet (S1) and second sheet (S2) are compressed so as toimpregnate the thermosetting resin in filaments of fiber bundles.Accordingly, raw material (R) of an SMC is obtained with thethermosetting resin impregnated in filaments of fiber bundles CF.

Raw material R of an SMC is wound in a roll and transferred to the nextstep. Raw material R of an SMC is cut to predetermined lengths andshipped as a final product of sheet-type SMCs (fiber-reinforced resinmolding material). Note that first sheet (S1) and second sheet (S2) arepeeled off from the SMC prior to the molding process of the SMC.

The present invention is not limited to the above embodiments. Variousmodifications are possible within a scope that does not deviate from thegist of the present invention.

More specifically, in fiber bundle supply unit 10, instead of theaforementioned multiple rotary blades 18, multiple saw blades 38 asshown in FIGS. 4A and 4B, for example, may be used. FIG. 4A is a sideview showing another structural example of the fiber bundle supply unitequipped with the SMC production, apparatus shown in FIG. 1. FIG. 4B isa front view of the separation unit seen from the transport direction.

Multiple saw blades 38 are disposed at predetermined intervals in awidth direction (axis (Y) direction) of opened fiber bundle CF. Also, ineach saw blade 38, a series of multiple teeth 38 a are aligned in adirection the same as the transport direction of a fiber bundle CF. Insaw blades 38, positions of multiple teeth 38 a in the transportdirection are preferred to correspond to each other. By so setting,piercing is more easily done by teeth 38 a of multiple saw blades 38aligned in a width direction of a fiber bundle CF.

Among saw blades 38, spacer members 38 b are positioned. The uppersurface of a spacer member 38 b is positioned slightly above the borderof each of teeth 38 a (blade base).

On both sides of multiple saw blades 38 in the transport direction,paired guide members 40 are positioned. Relative to a fiber bundle CFtransported between paired guide members 40, multiple saw blades 38 arepositioned on the side opposite where paired guide members 40 arearranged and are set to be capable of making a vertical reciprocating(oscillating) motion between a position where multiple teeth 38 a piercea fiber bundle CF and a position away from the fiber bundle CF.

In other words, in a separation step using saw blades 38, a fiber bundleCF is separated in a width direction by multiple teeth 38 aintermittently piercing the opened fiber bundle CF while saw blades 38oscillate vertically (axis (Z) direction). During that time, multipleteeth 38 a pierce to the point where spacer members 38 b make contactwith a continuous fiber bundle CF so as to prevent the fiber bundle CFfrom continuously being separated by, teeth 38 a. Accordingly, the sameas in using the aforementioned rotary blades 18, multiple separatedfiber bundles CF are partially unseparated.

Therefore, in the above embodiment, separated fiber bundles CF aresupplied to cutter 13A in a stable condition while avoiding beingimpacted by meandering fiber bundles CF or askew, meandering orentangled filaments that may occur in fiber bundles CF.

Moreover, using relatively low-cost large-tow fiber bundles CF, theproduction cost of an SMC is reduced.

In the present invention, in a separation step using rotary blades 18 orsaw blades 38, for example, equipped in an SMC production apparatus asdescribed above, it is an option to laminate continuous fiber bundles CFin a thickness direction and separate them into multiple fiber bundlesCF.

Moreover, the above-mentioned teeth (18 a, 38 a) are not limitedspecifically, as long as they are capable of intermittently piercing acontinuous fiber bundle CF. For example, teeth (18 a, 38 a) may havesuch shapes that are shown in FIGS. 5A˜5E. Moreover, teeth (18 a, 38 a)may each be single-beveled or double-beveled.

Furthermore, among multiple rotary blades 18 or saw blades 38 positionedadjacent in a width direction (axis (Y) direction), the timing of teeth(18 a, 38 a) intermittently piercing a fiber bundle CF is not limited tocorresponding with each other, and the timing may be shifted from eachother.

Yet furthermore, when the angle of the tip of a blade (point angle)shown in FIG. 6A is set as “α” and the angle of a blade (cutting edgeangle) shown in FIG. 6B as “β,” teeth (18 a, 38 a) are preferred to haveangles that satisfy 30°≤α≤90° and 10°≤β≤45° (more preferably 20°≤β≤30°).The thickness of teeth (18 a, 38 a) is preferred to be set at 0.3˜2 mm.

It is an option for the production apparatus of a fiber-reinforced resinmolding material related to the present invention not to include anopening unit.

In the following, the effects of the present invention are made evenclearer by the examples below. The present invention is not limited tothose examples, and may be practiced through appropriate modificationsmade within a scope that does not deviate from the gist of the presentinvention.

Example 1

An SMC was produced by using the above-mentioned) SMC apparatus shown inFIGS. 1 and 2.

A separation unit having four rotary blades 18 was used. In each rotaryblade 18, a series of six teeth 18 a Were aliened in a circumferentialdirection. Each of teeth 18 a is set to be substantially triangular,having a maximum thickness of 1 mm at the portion that makes contactwith a fiber bundle CF, a maximum width of 1 mm at the portion of theblade that makes contact with a fiber bundle, an angle of 64° at the tipof the blade in a width direction (point angle), and an angle of 30° ina thickness direction of the blade (cutting edge angle). Among rotaryblades 18, positions of multiple teeth 18 a were set to correspond toeach other in a circumferential direction. Spacer members 18 b arepositioned among rotary blades 18, and the width of each spacer member18 b was set at 2.2 m.

A carbon fiber bundle (product name: TR 50S15L, number of fibers 15000,made by Mitsubishi Rayon Co., Ltd.) was used for a fiber bundle CF. Avinyl ester resin was used as paste (P).

The fiber bundle CF was widened to have a width of 15 mm by opening bars17. The transport speed of fiber bundle CF during a separation step was40 m/min. When separated by using four rotary blades 18, 28.3 mm-longseparated portions and 0.5 mm-long unseparated portions were alternatelyformed continuously′ in a longitudinal direction of the opened fiberbundle CF, while such portions were formed in four rows, being separatedat 3 mm-intervals in a width direction of fiber bundle CF. Separatedfiber bundles CF were cut by cutter 13A every 25.4 mm in a longitudinaldirection. Cut fiber bundles CF were spread on paste (P) coated on firstsheet (S1). The value of “a/L” was 1.11, and “a/(a+b)” was 0.98.

In the above production of SMC, separated fiber bundles CF were suppliedto cutting unit 13 in a stable condition without such an incident assome fiber bundles wrapping around rolls or the like. Some cut fiberbundles CF contained unseparated portions, but the amount was not atsuch a level that would affect the dispersibility of fiber bundles CF onpaste (P). The quality of the obtained SMC was substantially the same asan SMC formed with chopped carbon fiber bundles of the same sizeprepared by, using a carbon fiber bundle CF with a smaller number offibers (number of fibers: 3000) without going through a separation step.

Example 2

An SMC was produced by using the above-mentioned SMC apparatus shown inFIGS. 1 and 2.

A separation unit having one rotary blade 18 was used. Each of teeth 18a was set to be substantially triangular, having a maximum thickness of0.5 mm at the portion that makes contact with a fiber bundle CF, amaximum width of 0.5 mm at the portion of the blade that makes contactwith a fiber bundle, an angle of 64° at the tip of the blade in a widthdirection (point angle), and an angle of 30° in a thickness direction ofthe blade (cutting edge angle). Among rotary blades 18, positions ofmultiple teeth 18 a were set to correspond to each other in acircumferential direction. Spacer members 18 b are positioned amongrotary blades 18, and the width of each spacer member 18 b is set at24.5 mm.

A carbon fiber bundle (product name: TRW40 50L, number of fibers 50000,made by Mitsubishi Rayon Co., Ltd.) was used for a fiber bundle CF. Avinyl ester resin was used as paste (P).

The fiber bundle CF was widened to have a width of 25 mm by usingopening bars 17. The transport speed of fiber bundle CF during aseparation step was 40 m/min. When separated by using four rotary blades18, 28.3 mm-long separated portions and 0.6 mm-long unseparated portionswere formed in the opened fiber bundle CF. Separated fiber bundle CF wascut by cutter 13A every 25.4 mm in a longitudinal direction. Cut fiberbundles CF were, spread on paste (P) coated on first sheet (S1). Thevalue of “a/L” was 1.11, arid “a/(a+b)” was 0.98.

In the above production of SMC, separated fiber bundles CF were suppliedto cutting unit 13 in a stable condition without such an incident assome fiber bundles wrapping around rolls or the like. Some cut fiberbundles CF contained unseparated portions, but the amount was not atsuch a level that would affect the dispersibility of fiber bundles CF onpaste (P). The quality of the obtained SMC was substantially the same asan SMC formed with chopped carbon fiber bundles of the same sizeprepared by using a carbon fiber bundle CF with a smaller number offibers (number of fibers: 3000) without going through a separation step.

Comparative Example 11

Using the same apparatus as in Example 1, a carbon fiber bundle (productname: TR 50S15L, number of fibers 15000, made by Mitsubishi Rayon Co.,Ltd.) was used. The fiber bundle CF was widened to have a width of 15 mmby opening bars 17. The transport speed of fiber bundle CF during aseparation step was 40 m/min. When separated by using four rotary blades18, 20.4 mm-long separated portions and 1 mm-long unseparated portionswere alternately aligned continuously in a longitudinal direction of theopened fiber bundle CF, while such portions were formed in four rows,being separated at 3-mm intervals in a width direction of the fiberbundle CF. The separated fiber bundles CF were cut by cutter 13A every25.4 mm in a longitudinal direction. Cut fiber bundles CF were, spreadon paste (P) coated on first sheet (S1). The value of “a/L” was 0.8, and“a/(a+b)” was 0.95.

In the above production of SMC, separated fiber bundles CF were suppliedto cutting unit 13 in a stable condition without such an incident assome fiber bundles wrapping around rolls or the like. Some cut fiberbundles CF contained unseparated portions, but the amount was not atsuch a level that would affect the dispersibility, of fiber bundles CFon paste (P). Regarding the quality of, the obtained SMC, since some ofthe cut fiber bundles were undetached, its strength was about 30% lowerthan in an SMC formed with chopped carbon fiber bundles of the same sizeprepared by using a carbon fiber bundle CF with a smaller number of,fibers (number of fibers: 3000) without going through a separation step.

Comparative Example 2

Using the same apparatus as in Example 1, a carbon fiber bundle (productname: TR 50S15L, number of fibers 15000, made by Mitsubishi Rayon Co.,Ltd.) was used. The fiber bundle CF was widened to have a width of 15 mmby opening bars 17. The transport speed of fiber bundle CF during aseparation step was 40 m/min. When separated by using four rotary blades18, 28.3 mm-long separated portions and 3.5 mm-long unseparated portionswere alternately formed continuously in a longitudinal direction of theopened fiber bundle CF, while such portions were formed in four rows,being separated at 3 mm intervals in a width direction of the fiberbundle CF. Separated fiber bundles CF were cut by cutter 13A every 25.4mm in a longitudinal direction. Cut fiber bundles CF were spread onpaste (P) coated on first sheet (S1). The value of “a/L” was 1.11, and“a/(a+b)” was 0.89.

In the above production of SMC, separated fiber bundles CF were suppliedto cutting unit 13 in a stable condition without such an incident assome fiber bundles wrapping around rolls or the like. Some cut fiberbundles CF contained unseparated portions, but the amount was not atsuch a level that would affect the dispersibility of fiber bundles CFoar paste (P). Regarding the quality of the obtained SMC, since some ofthe cut fiber bundles were undetached, its strength was about 30% lowerthan in an SMC formed with chopped carbon fiber bundles of the same sizeprepared by using a carbon fiber bundle CF with a smaller number offibers (number of fibers: 3000) without going through a separation step.

Comparative Example 3

Using the same apparatus as in Example 1, a carbon fiber bundle (productname: TR 50S15L, number of fibers 15000, made by Mitsubishi Rayon Co.,Ltd.) was used. The fiber bundle CF was widened to have a width of 15 mmby opening bars 17. The transport speed of fiber bundle CF during aseparation step was 40 m/min. When separated by using four rotary blades18, 28.3 mm-long separated portions and 0 mm-long unseparated portionsare alternately aligned continuously in a longitudinal direction of theopened fiber bundle CF, while such portions are formed in four rows,being separated at 3-mm intervals in a width direction of fiber bundleCF. Separated fiber bundles CF were cut, by cutter 13A every 25.4 mm ina longitudinal direction. Cut fiber bundles CF were spread on paste (P)coated on first sheet (S1). The value of “a/L” was 1.11, and “a/(a+b)”was 1.

In the above production of SMC, some separated fiber bundles CF werewrapped around rolls or the like, and an SMC was unable to be obtained.

DESCRIPTION OF NUMERICAL REFERENCES

-   10 ⋅ ⋅ ⋅ fiber bundle supply unit, 11 ⋅ ⋅ ⋅ first sheet supply unit,    12 ⋅ ⋅ ⋅ first coating unit, 13 ⋅ ⋅ ⋅ cutting unit, 13A ⋅ ⋅ ⋅    cutter, 14 ⋅ ⋅ ⋅ second sheet supply unit, 15 ⋅ ⋅ ⋅ second coating    unit, 16 ⋅ ⋅ ⋅ impregnation unit, 18 ⋅ ⋅ ⋅ rotary blade, 18 a ⋅ ⋅ ⋅    tooth, 18 b ⋅ ⋅ ⋅ spacer member, 20 ⋅ ⋅ ⋅ first transport unit, 28 ⋅    ⋅ ⋅ second transport unit, 31 ⋅ ⋅ ⋅ lamination mechanism, 32 ⋅ ⋅ ⋅    compression mechanism. 38 ⋅ ⋅ ⋅ saw blade, 38 a ⋅ ⋅ ⋅ saw tooth, 38    b ⋅ ⋅ ⋅ spacer member, 40 ⋅ ⋅ ⋅ guide member, CF ⋅ ⋅ ⋅ fiber bundle,    P ⋅ ⋅ ⋅ paste (thermosetting resin), S1 ⋅ ⋅ ⋅ first sheet, S2 ⋅ ⋅ ⋅    second sheet, S3 ⋅ ⋅ ⋅ laminated sheet, R ⋅ ⋅ ⋅ raw material of SMC    (fiber-reinforced resin molding material)

1. A method for producing a sheet-type fiber-reinforced resin moldingmaterial comprising impregnating a resin among filaments of cut fiberbundles, wherein the cut fiber bundles are obtained by intermittentlyseparating a continuous fiber bundle in a longitudinal direction and bycutting the fiber bundle at intervals in the longitudinal direction tosatisfy the condition specified in formula (1) below:1≤a/L  (1) in formula (1), “a” is a length of a separated portion of thecontinuous fiber bundle, and “L” is the interval for cutting the fiberbundle in a longitudinal direction.
 2. The method for producing afiber-reinforced resin molding material according to claim 1, whereinthe separation and cutting are conducted to satisfy the conditionspecified in formula (2) below:a/L≤10  (2).
 3. A method for producing a sheet-type fiber-reinforcedresin molding material comprising impregnating a resin among filamentsof cut fiber bundles, wherein the cut fiber bundles are obtained byintermittently separating a continuous fiber bundle in a longitudinaldirection and by cutting the fiber bundle at intervals in thelongitudinal direction to satisfy the condition specified in formula (3)below:0.9≤a/(a+b)<1  (3) in formula (3), “a” is a length of a separatedportion of the continuous fiber bundle, and “b” is a length of anunseparated portion that is present between portions intermittentlyseparated in the continuous fiber bundle.
 4. The method for producing afiber-reinforced resin molding material according to claim 1, whereinthe resin is a thermosetting resin.
 5. The method for producing afiber-reinforced resin molding material according to claim 1, whereinthe intermittent separation is conducted by intermittently piercing thecontinuous fiber bundle with a blade.
 6. The method for producing afiber-reinforced resin molding material according to claim 1, wherein aseries of a plurality of blades, aligned at predetermined intervals in awidth direction of the continuous fiber bundle, pierce the continuousfiber bundle intermittently so as to form partially unseparated portionsamong a plurality of separated fiber bundles.
 7. The method forproducing a fiber-reinforced resin molding material according to claim1, comprising: a step for coating a resin-containing paste on a firstsheet transported in a predetermined direction; a step for separating acontinuous fiber bundle into a plurality of fiber bundles; a step forcutting the separated fiber bundles with a cutter and spreading the cutfiber bundles on the paste; and a step for impregnating the resin amongfilaments of the fiber bundles by laminating a second sheet with thecoated paste on the first sheet with the fiber bundles spread thereonand by compressing the paste and fiber bundles sandwiched between thefirst and second sheets.
 8. The method for producing a fiber-reinforcedresin molding material according to claim 7, wherein in the step forseparating a continuous fiber bundle into a plurality of fiber bundles,a plurality of rotary blades, aligned at predetermined intervals in awidth direction of a continuous fiber bundle and each having a series ofa plurality of teeth in its circumferential direction, are used so thatthe plurality of teeth intermittently pierce the continuous fiber bundlewhile the plurality of rotary blades rotate.
 9. The method for producinga fiber-reinforced resin molding material according to claim 7, whereinin the step for separating a continuous fiber bundle into a plurality offiber bundles, saw blades with the plurality of teeth, aligned in adirection the same as the transport direction of the fiber bundle, areused so that the plurality of teeth intermittently pierce the continuousfiber bundle while the saw blades oscillate vertically.
 10. The methodfor producing a fiber-reinforced resin molding material according toclaim 7, wherein in the step for separating a continuous fiber bundleinto a plurality of fiber bundles, continuous fiber bundles arelaminated in a thickness direction and are separated into a plurality offiber bundles.
 11. The method for producing a fiber-reinforced resinmolding material according to claim 7, wherein in the step forseparating a continuous fiber bundle into a plurality of fiber bundles,the continuous fiber bundle is opened in the width direction, and thenthe opened fiber bundle is separated into a plurality of fiber bundles.12. An apparatus for producing a sheet-type fiber-reinforced resinmolding material that is formed by impregnating a resin among filamentsof cut fiber bundles, comprising: a separation unit for separating acontinuous fiber bundle into a plurality of fiber bundles; and a cuttingunit for cutting separated fiber bundles by using a cutter, wherein theseparation unit forms unseparated portions among a plurality ofseparated fiber bundles by intermittently piercing the continuous fiberbundle with a blade.
 13. The apparatus for producing a fiber-reinforcedresin molding material according to claim 12, wherein the blade is setto be a series of a plurality of blades aligned at predeterminedintervals in a width direction of the continuous fiber bundle.
 14. Theapparatus for producing a fiber-reinforced resin molding materialaccording to claim 12, comprising: a coating unit for coating aresin-containing paste on a first sheet transported in a predetermineddirection; the separation unit; a cutting unit for cutting the separatedfiber bundles with a cutter and spreading the cut fiber bundles on thepaste; and an impregnation unit for impregnating the resin amongfilaments of the fiber bundles by laminating a second sheet with thecoated paste on the first sheet with the fiber bundles spread thereonand by compressing the paste and fiber bundles sandwiched between thefirst and second sheets.
 15. The apparatus for producing afiber-reinforced resin molding material according to claim 12, whereinthe separation unit comprises rotary blades with a plurality of teethaligned in its circumferential direction, and the plurality of teethpierce the continuous fiber bundle intermittently when the rotary bladesrotate.
 16. The apparatus for producing a fiber-reinforced resin moldingmaterial according to claim 12, wherein the separation unit comprisessaw blades with a plurality of teeth aligned in a direction the same asthe transport direction of the fiber bundle and the plurality of teethintermittently pierce a continuous fiber bundle while the saw bladesoscillate vertically.
 17. The apparatus for producing a fiber-reinforcedresin molding material according to claim 12, further comprising pairedguide members positioned on both sides of the blade in the transportdirection, and from the side opposite where the paired guide members arepositioned, the blade pierces the continuous fiber bundle transportedbetween the paired guide members.
 18. The apparatus for producing afiber-reinforced resin molding material according to claim 13, furthercomprising a spacer member positioned between the plurality of bladesaligned in a width direction, wherein the plurality of blades pierce thecontinuous fiber bundle up to the point where the spacer member makescontact with the bundle.
 19. The method for producing a fiber-reinforcedresin molding material according to claim 3, wherein the resin is athermosetting resin.
 20. The method for producing a fiber-reinforcedresin molding material according to claim 19, wherein the intermittentseparation is conducted by intermittently piercing the continuous fiberbundle with a blade.
 21. The method for producing a fiber-reinforcedresin molding material according to claim 19, wherein a series of aplurality of blades, aligned at predetermined intervals in a widthdirection of the continuous fiber bundle, pierce the continuous fiberbundle intermittently so as to form partially unseparated portions amonga plurality of separated fiber bundles.
 22. The method for producing afiber-reinforced resin molding material according to claim 19,comprising: a step for coating a resin-containing paste on a first sheettransported in a predetermined direction; a step for separating acontinuous fiber bundle into a plurality of fiber bundles; a step forcutting the separated fiber bundles with a cutter and spreading the cutfiber bundles on the paste; and a step for impregnating the resin amongfilaments of the fiber bundles by laminating a second sheet with thecoated paste on the first sheet with the fiber bundles spread thereonand by compressing the paste and fiber bundles sandwiched between thefirst and second sheets.
 23. The method for producing a fiber-reinforcedresin molding material according to claim 22, wherein in the step forseparating a continuous fiber bundle into a plurality of fiber bundles,a plurality of rotary blades, aligned at predetermined intervals in awidth direction of a continuous fiber bundle and each having a series ofa plurality of teeth in its circumferential direction, are used so thatthe plurality of teeth intermittently pierce the continuous fiber bundlewhile the plurality of rotary blades rotate.
 24. The method forproducing a fiber-reinforced resin molding material according to claim22, wherein in the step for separating a continuous fiber bundle into aplurality of fiber bundles, saw blades with the plurality of teeth,aligned in a direction the same as the transport direction of the fiberbundle, are used so that the plurality of teeth intermittently piercethe continuous fiber bundle while the saw blades oscillate vertically.25. The method for producing a fiber-reinforced resin molding materialaccording to claim 22, wherein in the step for separating a continuousfiber bundle into a plurality of fiber bundles, continuous fiber bundlesare laminated in a thickness direction and are separated into aplurality of fiber bundles.
 26. The method for producing afiber-reinforced resin molding material according to claim 22, whereinin the step for separating a continuous fiber bundle into a plurality offiber bundles, the continuous fiber bundle is opened in the widthdirection, and then the opened fiber bundle is separated into aplurality of fiber bundles.